This invention relates to cassettes for holding x-ray film and the like.
Cassettes used to hold x-ray sensitive film or like material are widely used in medical and other disciplines requiring x-ray explorations. Typically, cassettes are used with x-ray machines found in hospitals, doctor's offices, and tuberculosis testing stations.
In general, such cassettes include a radiolucent box or tray and a mating cover or lid within which x-ray film can be disposed, usually in a planar configuration, for contact with an intensifying screen. After a cassette is loaded with x-ray film, it is inserted into an x-ray machine, the film is exposed, and the cassette is delivered to a development laboratory. Here, the film is removed and developed and the cassette is reloaded for subsequent use.
These cassettes must, of course, maintain a lighttight configuration when in use, to avoid accidentally exposing the x-ray film to visible spectrum light. Such accidental exposure can fog the film, and may render the x-ray exposure itself unusable.
Many presently offered x-ray cassettes are heavy and expensive. Some require the use of expensive parts formed to close tolerances to provide the requisite lighttight seal. Such parts can become worn, and hard usage or accidental droppage can permanently maladjust the parts, thereby rendering the cassette useless.
Moreover, some prior x-ray cassettes utilize hinges and latching devices to secure the lid and tray members in mutually light-tight configurations. The complexity of these latches and hinges can make insertion and removal of the film difficult, especially when inexperienced personnel are hurried by the force of circumstances. The latches and hinges are complex because they are highly stressed when in use; high stresses are needed to keep the cassette interior light-tight, and to keep the x-ray film flat and pressed into intimate engagement with the intensifying screen.
It is accordingly the general object of this invention to provide an inexpensive and highly commercial cassette holder for x-ray films and the like.
It is a more specific object of the invention to provide a cassette having a tray and mating lid which are automatically urged into tight engagement when they are closed together. A related object is to provide a cassette wherein the lid can be propped in an open position, or completely removed from the tray when desired.
It is another specific object of the invention to provide a cassette which will maintain itself in a closed condition without using complex or highly stressed latching devices. A related object is to provide a cassette which tends to stay closed even when dropped or handled roughly. Another related object is to provide a cassette having a latch which shows at a glance whether or not the cassette parts are locked in a closed position.
It is a further object of the invention to provide a cassette which provides a relatively high degree of light security without the use of expensive or complex parts or high stresses.
Other objects and advantages of the invention will become apparent upon reading the following detailed description, and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.